docs: update documentation for completed placeholder implementations

- Update plan file to mark all implementations as completed
- Update blockchain-node.md to document HMAC-SHA256 MAC computation in keystore
- Add Agent Integration Service section to coordinator-api.md documenting:
  - Systemd-based deployment
  - Health checks with systemd + HTTP monitoring
  - Instance lifecycle management (deployment, removal, rollback)
  - Metrics collection with database fallback
  - Configurable alerting rules

docs/apps/blockchain/blockchain-node.md

@@ -127,7 +127,8 @@ The node can run multiple chains simultaneously by setting `supported_chains` in
 ## Keystore Management
 
 ### Encrypted Keystore Format
-- Uses Web3 keystore format (AES‑256‑GCM + PBKDF2).
+- Uses Web3 keystore format (AES‑256‑GCM + PBKDF2 + HMAC-SHA256 MAC).
+- MAC computed over derived_key[16:32] + ciphertext for password validation.
 - Password stored in `keystore/.password` (chmod 600).
 - Private keys are **never** stored in plaintext.
 

docs/apps/coordinator/coordinator-api.md

@@ -66,6 +66,28 @@ The multi-modal RL router proxies to the AI service for job management:
 
 All endpoints use `AITBCHTTPClient` to proxy requests to the AI service (default port 8106). When the AI service is unavailable, endpoints return error responses indicating the service is unreachable.
 
+## Agent Integration Service
+
+The agent integration service provides deployment and management capabilities for agent instances:
+
+- **Systemd-based Deployment**: Agent instances are deployed as systemd services with automatic startup and monitoring
+- **Health Checks**: HTTP health checks combined with systemd status monitoring for instance health tracking
+- **Instance Lifecycle**: Full lifecycle management including deployment, removal, and rollback to previous versions
+- **Metrics Collection**: Automatic metrics collection from agent endpoints with database fallback for monitoring
+- **Alerting Rules**: Configurable alerting thresholds for CPU, memory, error rate, and response time monitoring
+
+### Deployment Features
+- Dynamic systemd service file generation
+- Service enablement and automatic startup
+- Startup monitoring with active status verification
+- Graceful failure handling with cleanup
+
+### Monitoring Features
+- Multi-source health checks (systemd + HTTP endpoints)
+- Historical health check tracking (last 100 checks)
+- Metrics aggregation with fallback to database values
+- Configurable alert thresholds and channels
+
 ## Development Setup
 
 1. Create a virtual environment in `apps/coordinator-api/.venv`.